Recently, research into an apparatus that uses an LED (light emitting device) as a light emitting device has been actively conducted.
The LED converts an electric signal into an optical signal using the characteristics of a compound semiconductor. The LED comprises a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer which are stacked on a substrate. As the LED is powered on, the active layer emits light.
The first conductive semiconductor layer may be an N type semiconductor layer and the second conductive semiconductor layer may be a P type semiconductor layer, and vice versa.
Since the LED may be broken by backward bias or ESD (electrostatic discharge) current, a device for protecting the LED from the backward bias or ESD current is mounted at the LED in the package process of the LED.
For example, a Zener diode is properly aligned to prevent the LED from being broken by the backward bias or ESD current.
However, since the size of an LED package has become reduced, mounting the Zener diode in the LED package may be difficult and the cost required for the package process may be increased.